On the choice of outlet boundary conditions for patient-specific analysis of aortic flow using computational fluid dynamics

Boundary conditions (BCs) are an essential part in computational fluid dynamics (CFD) simulations of blood flow in large arteries. Although several studies have investigated the influence of BCs on predicted flow patterns and hemodynamic wall parameters in various arterial models, there is a lack of comprehensive assessment of outlet BCs for patient-specific analysis of aortic flow. In this study, five different sets of outlet BCs were tested and compared using a subject-specific model of a normal aorta. Phase-contrast magnetic resonance imaging (PC-MRI) was performed on the same subject and velocity profiles extracted from the in vivo measurements were used as the inlet boundary condition. Computational results obtained with different outlet BCs were assessed in terms of their agreement with the PC-MRI velocity data and key hemodynamic parameters, such as pressure and flow waveforms and wall shear stress related indices. Our results showed that the best overall performance was achieved by using a well-tuned three-element Windkessel model at all model outlets, which not only gave a good agreement with in vivo flow data, but also produced physiological pressure waveforms and values. On the other hand, opening outlet BCs with zero pressure at multiple outlets failed to reproduce any physiologically relevant flow and pressure features.

The subgingival microbiomes in periodontitis and health of individuals with rheumatoid arthritis and at risk of developing rheumatoid arthritis

Serum anti-citrullinated protein antibodies (ACPAs), present in 70% of people with rheumatoid arthritis (RA), can be detected ≤10years before the onset of clinical disease. RA and periodontitis are epidemiologically associated and we have reported a high incidence of periodontitis in people who are ACPA+ and at risk of RA. Periodontal bacteria may contribute by multiple routes to the generation of RA-autoantibodies. This study aims to characterise the subgingival microbiomes from periodontitis and health in individuals with/without RA and at risk of RA.

Forty-five ACPA+ no RA (RA-at-risk; RAR), 31 healthy controls (HC) and 30 ACPA+ RA patients (RA) underwent a periodontal examination. DNA from subgingival plaque from healthy and deep pocket sites were paired-end sequenced using the Illumina HiSeq3000 and data analysed using MG-RAST + DESeq.

Metagenomes in RA samples had high proportions of Actinobacteria; RAR microbiomes contained higher proportions of Bacteroidetes than HC. The relative abundance of P. gingivalis was high in periodontitis and RAR; Aggregatibacter actinomycetemcomitans was detected with similar frequency in each group. Other bacteria implicated in periodontitis and/or autoantibody generation (Filifactor alocis, Prevotella spp, Leptotrichia spp.) were detected. Analyses are on-going to elucidate the diversity and functional potential of the subgingival microbiome associated with RA.

MiR-15a expression analysis in non-small cell lung cancer A549 cells under local hypoxia microenvironment

OBJECTIVE

Lung cancer is a common tumor in the clinic. Hypoxia is an important biological characteristic in the solid malignant tumor. MiRNA participates in cell proliferation, differentiation, and apoptosis. This study tested hypoxia-inducible factor 1-α (HIF-1α) in lung cancer patients and analyzed the microRNA-15a (miR-15a) expression in A549 cells under different local hypoxia microenvironments.

PATIENTS AND METHODS

A total of 40 non-small cell lung cancer (NSCLC) patients in First Affiliated Hospital of Zhengzhou University between Jan 2015 and Jan 2016 were involved in this study. The serum and tissue samples of lung cancer were collected. Serum HIF-1α level was tested by enzyme-linked immunosorbent assay (ELISA) assay. HIF-1α expression in tissue was evaluated by using the immunohistochemistry. A549 cells were cultured under normoxic, hypoxic, and anaerobic environment, respectively. HIF-1α mRNA and miR-15a levels were determined by RT-PCR.

RESULTS

HIF-1α levels were up-regulated in serum and tissue (p<0.05). HIF-1α mRNA increased, while miR-15a down-regulated in A549 from hypoxia and anaerobic groups compared with control (p<0.05). HIF-1α shRNA transfection significantly reduced HIF-1α and elevated miR-15a level (p<0.05). MiR-15a shRNA transfection exhibited no statistical impact on HIF-1α expression (p>0.05).

CONCLUSIONS

HIF-1α highly expressed in lung cancer patients. MiR-15a levels were down-regulated in A549 cells under hypoxia and anaerobic conditions.

Genetic analysis of HOXA11 gene in Chinese patients with cryptorchidism

Cryptorchidism is the most common congenital anomaly in male children. Its aetiology remains unknown in the majority of cases. Because HOXA11 plays a vital role in regulating testicular descent, genetic variants in HOXA11 genes may contribute to the risk of cryptorchidism. In this study, mutation analysis was performed on the HOXA11 gene in a cohort of 89 patients with cryptorchidism. Furthermore, an association analysis of the HOXA11 tag single nucleotide polymorphism rs6461992 was performed in 168 patients with unilateral cryptorchidism and 193 controls. No pathogenic mutations were found. A significant difference in genotype and allele distribution was detected between cases and controls (p = .029 and .022 respectively). These results suggest that mutations in the coding sequence of HOXA11 might not be a common cause of cryptorchidism, while common polymorphisms in the HOXA11 gene might contribute to the risk of developing unilateral cryptorchidism.

Pharmacokinetic/pharmacodynamic integration and modelling of oxytetracycline for the porcine pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida

Pharmacokinetic–pharmacodynamic (PK/PD) integration and modelling were used to predict dosage schedules of oxytetracycline for two pig pneumonia pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) were determined in broth and porcine serum. PK/PD integration established ratios of average concentration over 48 h (C_av0–48 h)/MIC of 5.87 and 0.27 μg/mL (P. multocida) and 0.70 and 0.85 μg/mL (A. pleuropneumoniae) for broth and serum MICs, respectively. PK/PD modelling of in vitro time–kill curves established broth and serum breakpoint values for area under curve (AUC_0–24 h)/MIC for three levels of inhibition of growth, bacteriostasis and 3 and 4 log₁₀ reductions in bacterial count. Doses were then predicted for each pathogen, based on Monte Carlo simulations, for: (i) bacteriostatic and bactericidal levels of kill; (ii) 50% and 90% target attainment rates (TAR); and (iii) single dosing and daily dosing at steady‐state. For 90% TAR, predicted daily doses at steady‐state for bactericidal actions were 1123 mg/kg (P. multocida) and 43 mg/kg (A. pleuropneumoniae) based on serum MICs. Lower TARs were predicted from broth MIC data; corresponding dose estimates were 95 mg/kg (P. multocida) and 34 mg/kg (A. pleuropneumoniae).

Testing Iron and Zinc Bioavailability in Genetically Enriched Beans (Phaseolus Vulgaris L.) and Rice (Oryza Sativa L.) in a Rat Model

A rat model was used to determine the bioavailability of iron and zinc in bean seeds and rice grain from enriched genotypes of these globally important staple foods. Seed and grain from the genotypes tested (intrinsically radiolabelled with either 59Fe or 65Zn) were cooked, homogenized in water, and lyophilized to dryness. The dried, radiolabelled powder was fed to young male rats in single meals. Bioavailability was calculated from the amount of radiolabelled iron and zinc retained in the rats over a 10-day period as determined each day by whole-body gamma spectrometry assay. The data collected demonstrate that increasing the amount of iron or zinc in enriched rice grain and bean seed significantly increases the amount of iron or zinc bioavailable to rats.

Although a rat model is not ideal for determining iron and zinc bioavailability to humans, because rats are much more efficient at absorbing iron and zinc from plant foods than humans, rats can be used to give relative estimates of bioavailable iron and zinc in plant foods. These estimates can be used to rank promising genotypes of staple foods for use in later feeding trials with humans, greatly reducing the numbers of genotypes that would have to be tested in humans without use of the rat model. Ultimately, because of the complexities of determining the bioavailability to humans of iron and zinc in plant foods, human feeding trials performed under free-living conditions should be conducted with the most promising genotypes before these genotypes are released for distribution to breeding programmes worldwide

Measuring Iron and Zinc Bioavailability in Humans

Iron and zinc deficiencies are common in populations dependent on cereal-based diets because of the poor bioavailability of these minerals in those foods. Selective breeding of high-mineral grains can improve the total intake of iron and zinc. However, the additional iron and zinc from those grains may not be available for absorption because of the high phytate content of cereals. Iron and zinc bioavailability needs to be measured before the high-mineral crops are promoted. Iron or zinc bioavailability can be measured from the response of a physiological variable, assessment of body retention, tissue or blood uptake, changes in pool size, or rates of absorption. Iron bioavailability is preferentially measured from erythrocyte uptake of oral radioactive or stable iron tracers; zinc bioavailability is measured from the rate of absorption of an oral isotopic tracer compared with an intravenous tracer. The oral label, which is required for studies of both iron and zinc, may be intrinsically added to the plant during growth or extrinsically added before feeding. Iron and zinc bioavailability from intrinsically and extrinsically labelled normal and high-mineral common bean varieties was tested in young women with low iron stores. The absorption of intrinsic and extrinsic labels of iron and zinc did not differ. The bioavailability of iron and zinc from both varieties was low, about 1.5% and 13%, respectively. Methods to improve the bioavailability of iron and zinc from plant foods need to be developed.

Correlation between polymorphisms in the glucocorticoid receptor gene NR3C1 and susceptibility to asthma in a Chinese population from the Henan Province

The aim of this study was to investigate the association between four single nucleotide polymorphisms in NR3C1 (Tth111I, BclI, ER22/23EK, and N363S), which encode the glucocorticoid receptor, and asthma susceptibility in patients from the Henan Province of China. Three hundred and twenty-eight patients with asthma and 60 healthy volunteers were recruited to this study. The target SNPs were genotyped by polymerase chain reaction (PCR)-high resolution melting and PCR-restriction fragment length polymorphism. The frequencies of the AA (8.84%) and GG (30.79%) genotypes of Tth111I were higher, and that of the AG genotype was lower (60.37%), in the asthma patients compared to that seen in healthy controls (5.00, 26.67, and 68.33%, respectively). On the other hand, asthma patients showed higher frequencies of the AA genotype (78.05%) of N363S, and lower frequencies of the AG and GG genotypes (15.55 and 6.40%), compared to healthy volunteers (71.67, 18.33, and 10.00%, respectively). Neither of these differences were found to be statistically significant. Moreover, we observed no significant differences in the genotype or allele frequencies of the BclI and ER22/23EK SNPs between the patient and control groups. In conclusion, SNPs in NR3C1 were not significantly associated with asthma in patients from the Henan Province. Patients showed higher frequencies of the AA and GG genotypes of Tth111I and the AA genotype of the N363S SNP compared to healthy volunteers, although these differences were not significant.